#include "stdio.h"

void swap(int *p1, int *p2) {
  int t1 = *p1;
  int t2 = *p2;
  *p1 = t2;
  *p2 = t1;
}

int main() {
  int a = 1, b = 2;
  swap(&a, &b);
  printf("a=%d,b=%d\n", a, b);
  return 0;
}